Antipsychotics

Question 1

Typical (1st generation) APs

Answer 1

CHLORPROMAZINE
aim - to antagonise (reduce) levels of DA in brain

Reduce levels of DA in the brain by binding to D2 receptor sites = Lowers DA transmission + Reduces positive symptoms
KAPUR - approx 60-75% D2 receptors blocked in mesolimbic pathway

Side effects:
bcs 60-75% D2 receptors sites were permanently blocked, DA levels become too low = aggravate negative symptoms.

Question 2

Atypical (2nd generation) APs

Answer 2

CLOZAPINE
Modulate (increase and/ decrease at the same time) levels of DA + ST in key DA pathways of the brain
Nigrostriatal pathway
Mesolimbic pathway

attaches to DA receptors + quickly dissociate themselves (hit + run) - RAPID DISSOCIATION

Side effects:
Dystonia
Tardive dyskinesia - it is typical due to 60% patients suffering from it

Question 3

describe the mode action of the mesolimbic DA pathway as a form of atypical APs SZ medication

Answer 3

this sensory pathway is involved with Emotions, sensations of pleasure
works by reducing the hyperactivity of DA = reduces positive symptoms (delusions)

workss by ‘hit and run’ action (rapid dissociation) - AP have their effect on DA receptors then quickly leave sites

this action ALLOWS APs to have an effect BUT THEN receptors quickly become available for naturally occurring DA before the next dose.

Helps avoid MOTOR SIDE EFFECTS.

Question 4

desrcibe the role of the Nigrostriatal DA pathway as a mode of action of atypical APS for SZ medication

Answer 4

this sensory pathway has a role of Controlling movements (involves DA and serotonin) - blocking/ reducing DA receptor sites = MOTOR SIDE EFFECTS

Serotonin’s presence in this pathway inhibits/ reduces DA, so APs block serotonin receptors = increase natural DA levels
HENCE, natural DA fills receptor sites + prevents blockade from APs

Tackles negative symptoms + REDUCES MOTOR SIDE EFFECTS.

COMBATS HYPO + HYPERMINERGIA at the same time

Question 5

Positive EV APs

Answer 5

DAVIS - meta analysis,29 studies
55% APs swapped with placebo = relapsed
19% APs remained = relapsed
= effective

Question 6

EV Negative APs

Answer 6

Side effects - tardive dyskinesia - irreversible
Jerky and uncontrollable facial movements
20-40% experienced tremors and righty legs
= ethical dilemma